The present invention generally relates to methods and apparatuses for slicing products. The invention particularly relates to machines having a cutting head equipped with at least one knife suitable for slicing products into slices, wherein the cutting head is configured to promote the stability of the products during slicing.
Various types of equipment are known for slicing, shredding and granulating food products, such as vegetable, fruit, dairy, and meat products. A widely used line of machines for this purpose is commercially available from Urschel Laboratories, Inc., under the name Urschel Model CC®, an embodiment of which is represented in FIG. 1. The Model CC® machine line provides versions of centrifugal-type slicers capable of producing uniform slices, strip cuts, shreds and granulations of a wide variety of products at high production capacities. When used to produce potato slices for potato chips, the Model CC® line of machines can make use of substantially round potatoes to produce the desired circular chip shape with a minimum amount of scrap.
The Model CC® machine 10 schematically represented in FIG. 1 includes a cutting head 12 mounted on a support ring 15 above a gear box 16. A housing 18 contains a shaft coupled to the gear box 16 that rotates an impeller 14 within the cutting head 12 about an axis 17 of the cutting head 12. Products are delivered to the cutting head 12 and impeller 14 through a feed hopper 11 located above the cutting head 12. In operation, the impeller 14 is coaxially mounted within the cutting head 12, which is generally annular-shaped with cutting knives (not shown) mounted at its perimeter. The impeller 14 rotates within the cutting head 12, while the latter remains stationary. The hopper 11 delivers products to the middle of the impeller 14, and centrifugal forces cause the products to move outward into engagement with the knives of the cutting head 12. Further descriptions pertaining to the construction and operation of Model CC® machines, including improved embodiments thereof, are contained in U.S. Pat. Nos. 5,694,824 and 6,968,765, the entire contents of which are incorporated herein by reference.
FIG. 2 is a perspective view of a cutting head 12 and FIGS. 3 and 4 are perspective and cross-sectional views, respectively, of an impeller 14 of types that can be used in the Model CC® machine of FIG. 1. Referring to FIG. 2, each knife 13 of the cutting head 12 projects radially inward toward the interior of the cutting head 12, generally in a direction opposite the rotation of the impeller 14 within the cutting head 12, and defines a cutting edge at its radially innermost extremity. As represented in FIGS. 3 and 4, the impeller 14 comprises generally radially-oriented paddles 28 disposed between a base 30 and an upper ring 32, the latter being omitted in FIG. 4 to reveal the interior of the impeller 14 and orientations of the paddles 28. A frustoconical-shaped flange 34 extends in a generally axial direction from the ring 32 to define an opening 36 through which food products enter the impeller 14. The paddles 28 have faces 38 that engage and direct the products 40 (e.g., potatoes) radially outward towards and against the knives 13 of the cutting head 12 as the impeller 14 rotates.
The cutting head 12 shown in FIG. 2 comprises a lower support ring 18, an upper support ring 20, and circumferentially-spaced support segments (shoes) 22. The knives 13 of the cutting head 12 are individually secured with clamping assemblies 26 to the shoes 22. Each clamping assembly 26 includes a knife holder 26A mounted to the radially inward-facing side of a shoe 22, and a clamp 26B mounted on the radially outward-facing side of a shoe 22 to secure the knife 13 to the knife holder 26A. The shoes 22 are represented as secured with bolts 25 to the support rings 18 and 20. The shoes 22 are equipped with coaxial pivot pins (not shown) that engage holes in the support rings 18 and 20. By pivoting on its pins, the orientation of a shoe 22 can be adjusted to alter the radial location of the cutting edge of its knife 13 with respect to the axis of the cutting head 12, thereby controlling the thickness of the sliced product. As an example, adjustment can be achieved with an adjusting screw and/or pin 24 located circumferentially behind the pivot pins. FIG. 2 further shows optional gate inserts 23 mounted to each shoe 22, which the product crosses prior to encountering the knife 13 mounted to the trailing shoe 22. Each gate insert 23 and its corresponding knife 13 define a gate opening whose width can be adjusted by pivoting the shoe 22 toward and away from the cutting edge of the knife casing 40. As such, the thickness of each slice produced by a knife 13 is determined by the gate opening, and specifically the radial distance between the cutting edge of a knife 13 and the adjacent trailing edge of a gate insert 23. As used herein, “trailing” refers to a position on a cutting head that follows or succeeds another in the direction of rotation of an impeller assembled with the cutting head, whereas “leading” refers to a position on a cutting head that is ahead of or precedes another in the direction opposite the impeller's rotation.
The knives 13 shown in FIG. 2 are depicted as having straight cutting edges for producing flat slices, though knives of other shapes can be installed in Model CC® machines to produce sliced, strip-cut, shredded and granulated products. A nonlimiting example is knives having cutting edges that define a periodic pattern of peaks and valleys when viewed edgewise. The periodic pattern can be characterized by sharp peaks and valleys, or a more corrugated or sinusoidal shape characterized by more rounded peaks and valleys when viewed edgewise. If the peaks and valleys of each knife are aligned with those of the immediate leading knife, slices are produced in which each peak on one surface of a slice corresponds to a valley on the opposite surface of the slice, such that the slices can be substantially uniform in thickness but have a cross-sectional shape that is characterized by sharp peaks and valleys (“V-slices”) or a more corrugated or sinusoidal shape (crinkle slices), collectively referred to herein as periodic shapes. Alternatively, shredded product can be produced if each peak of each knife is aligned with a valley of the immediate leading knife, and waffle/lattice-cut product can be produced by intentionally making off-axis alignment cuts with a periodic-shaped knife, for example, by crosscutting a product at two different angles, typically ninety degrees apart. In addition, strip-cut and granulated products can be produced with the use of additional knives and/or cutting wheels located downstream of the knives. Whether a sliced, strip-cut, shredded, granulated, or waffle-cut product is desired will depend on the intended use of the product.
Though flat gate inserts are commonly used for a variety of slicing applications, the gate inserts 23 represented in FIG. 2 have ribs that define raised edges to create a row of openings that precede each knife 13 and through which rocks, sand, and other debris can exit the cutting head 12 without damaging the knives 13 and knife holders 26A. As taught in U.S. Patent Application Publication No. 2014/0007751, to promote phase alignment of potato chips having large-amplitude corrugations, large-amplitude corrugated shoes and gate inserts may be used in combination with large-amplitude corrugated knives for the purpose of maintaining product alignment during slicing.
Model CC® machines such as represented in FIGS. 1-4 are well suited for producing slices from a wide variety of food products. Even so, certain operating conditions can impact the ability of these machines to produce slices of uniform thickness at high production capacities. For example, FIG. 5 schematically represents four shoe sections of the cutting head of FIG. 2 and a condition that may occur that can lead to variability in thicknesses of slices 42 produced during a slicing operation. Water is commonly used as a lubricating fluid in food processing equipment, and a hydroplaning effect occurs to some degree between the products 40 (represented as potatoes) and the shoes 22 and gate inserts 23 prior to and during the slicing operation. Ordinarily, some degree of hydroplaning is desirable, consistent with the intent that the water serves as a lubricant between the products 40 and the interior surfaces of the shoes 22 and gate inserts 23. However, there is a growing trend to recycle water used in such equipment to conserve water and promote the environmental friendliness of the process by reducing the amount of waste water produced. Particularly when slicing potatoes and other starchy food products, the result is that the water may contain a significant amount of starch solids that increase the viscosity of the water and may also behave as an abrasive on the surfaces of the shoes 22 and gate inserts 23. FIG. 5 represents a relatively thick water film 44 present between the products 40 and cutting head 12 and, notably, between the products 40 and the ribs 46 of the gate inserts 23 as more readily apparent from the detailed image in FIG. 5. Such a film 44 can lead to sufficient hydroplaning to cause instability of the products 40 while in contact with the shoes 22 and inserts 23, which can result in variability in the thicknesses of the slices 42. Though such slice variability may be very slight, it may be sufficient to impact the desired uniformity of certain products, for example, fried or baked potato chips, as a result of the possibility of over-cooked and/or under-cooked regions within individual chips.